Mystery Surrounding Blue Ring Nebula Solved, Astronomers Believe

PC: NASA/JPL-Caltech/M. Seibert (Carnegie Institution for Science)/K. Hoadley (Caltech)/GALEX Team

Astronomers have uncovered the 16-year-old mystery surrounding the Blue Ring Nebula – an unusual, large, faint blob of gas with a star at its center.

Astronomers think the nebula was created by the merger of two stars, and that they are seeing the system a few thousand years after the merger, when evidence of the collision is still apparent. With the help of NASA and W.M. Keck Observatory on Maunakea, the team has discovered the nebula appears to be the first known example of two stars merged into one at a young stage.

The nebula was discovered in 2004 when scientists with NASA’s space-based Galaxy Evolution Explorer (GALEX) spotted the mysterious faint blob of gas, according to a press release from W.M. Keck Observatory. Over the next 16 years, they studied it with multiple Earth- and space-based telescopes, including W.M. Keck Observatory on Maunakea, but the more they learned, the more mysterious it seemed.

A new study published online on Nov. 18 in the journal Nature may have cracked the case. By applying cutting-edge theoretical models to the slew of data that has been collected on this object, the authors pose the nebula – a cloud of gas in space – is likely composed of debris from two stars that collided and merged into a single star.

While merged star systems are thought to be fairly common, they are nearly impossible to study immediately after they form because they’re obscured by debris kicked up by the collision. Once the debris has cleared – at least hundreds of thousands of years later – they’re challenging to identify because they resemble non-merged stars.

“The Blue Ring Nebula appears to be the missing link: astronomers are seeing the star system only a few thousand years after the merger, when evidence of the union is still plentiful,” the release states. “It appears to be the first known example of a merged star system at this stage.”